The invention relates to a device for sterilizing containers, in particular plastic containers and in particular plastic parisons, and also a method for sterilizing containers, in particular plastic containers and in particular plastic parisons. It is pointed out that the invention is described below with reference to plastic parisons described is and also only plastic parisons will be discussed. However, the invention is also applicable correspondingly to the sterilization of containers and in particular of plastic containers. However, the invention is particularly suitable for plastic parisons, since these have a relatively low weight and can also be sterilized relatively simply with regard to their size.
The device for sterilizing plastic parisons comprises a sterilization chamber and a transport device disposed at least partially inside the sterilization chamber for moving the plastic parisons inside the sterilization chamber, wherein the transport device has at least one gripping system for engaging round and supporting the plastic parisons by means of a gripping clamp. Engaging round is understood to mean at least partially engaging round, and thus within the scope of the invention it is not absolutely necessary for the plastic parison to be completely engaged around in its circumferential direction.
Generic devices for sterilizing plastic parisons are already known from the prior art. In this case the plastic parisons are guided through a sterilization chamber by means of the transport device and during this transport they are for example sterilized by means of a sterilizing medium. In order to be able to appreciably improve the shelf life of sensitive products to be filled for example into PET bottles, before the filling process the number of germs in the containers must be significantly reduced. For this purpose various wet and dry aseptic methods are known in the field of filling technology, but because of the sometimes large bottle volumes these methods give rise to a high consumption of the sterilizing medium used (for example peracetic acid, H2O2, . . . ). Therefore further machine designs reduce the number of germs even before the plastic parisons are blow moulded. In this case the plastic parison runs through a treatment region, that is to say a sterilization chamber, in which the disinfection is achieved by gaseous or liquid sterilization media or by irradiation (UV radiation, electron beams).
However, devices which are known from the prior art for sterilizing the plastic parisons have the inherent disadvantage that they cannot meet the particularly high demands for disinfection performance (e.g. in the case of weakly acidic products to be filled). In general during the container handling it should be ensured that every region of the container comes into contact for a specific time with the sterilizing means, i.e. a sterilizing medium or the radiation. Such sterilization which is as comprehensive as possible and covers the greatest possible surface area is desirable in particular in the case of subsequent filling with weakly acidic products. In this case a problem is posed by the gripping system in that at the points where a gripping clamp is positively or non-positively engaged on the plastic parison, that is to say on contact surfaces between the gripping clamp and the plastic parison, sterilization by the sterilizing means is not possible or is only possible to an insufficient extent. In other words, such contact surfaces on an external surface of the plastic parison are concealed by the gripping clamp. As a result, disinfection of these contact surfaces on this external surface is not ensured or is at least difficult, which is problematic in particular in the mouth region close to the product to be filled.
Therefore an object to be achieved is to provide a cost-effective device for sterilizing plastic parisons in which an external surface of plastic parisons can be completely sterilized in the simplest manner possible.